1. Field of Invention
This invention is generally related to a rotating cylinder for treatment of materials and is specifically related to an apparatus for supporting and driving a rotating cylinder such as a cylindrical ultraviolet irradiator for the treatment of fluids.
2. Description of the Prior Art
It is well known to support a hollow cylinder with the axis inclined to permit a loose material or fluid to run through the cylinder along its inner peripheral wall while rotating the cylinder to spread the material over the inner surface in order to create a film. A known example of such an apparatus is an irradiator used for the ultraviolet treatment of blood. An example of a rotating cylindrical irradiator was manufactured by the J. J. Dill Company, Kalamazoo Mich. in the 1950's. In the irradiator there described, blood components are introduced into the upper end of an inclined rotating cylinder and allowed to gravity feed along the inner wall of the cylinder as it is rotated in order to allow the blood to form a thin film on the inner wall as it flows toward the lower discharge end. As the blood moves through the cylinder, it is subjected to an axially mounted ultraviolet lamp for irradiating the fluid flowing through the cylinder.
It has been found that by controlling the exposure of blood constituents to ultraviolet light that various foreign microorganisms in the blood supply can be altered or immobilized. For example, various strains of virus can be inactivated and thereafter used to develop a vaccine which may be injected into the blood supply of an animal in order to create a natural immunity to the virus. Such a method has been used to create influenza and rabies vaccines for a number of years.
Currently, the most prevalent use of irradiators for ultraviolet treatment of blood components is for generating serums from the blood of mammals. In a typical example, mammal or human blood is removed from a subject and the platelets are then centrifuged out of the plasma. The remaining serum or basically non-solid clear component of the blood is irradiated to inactivate any virus that happens to be present. This will also typically kill or immobilize any other microorganisms that may happen to be present in the sample. If the plasma is further fractionated, that is, divided into different fractions, such as, by way of example, fibrinogen, different globulin, and literally hundreds of subcomponents which can be segregated by any of the well known methods of separating plasma, each of the fractions can then also be treated using the same irradiating method.
Prior to the development of a practical method for treating large quantities of blood through cylindrical irradiation, a small sample was placed on a flat plate, such as a specimen slide or a microscope slide, and then exposed to ultraviolet light, or a small portion was allowed to flow through a small diameter, clear quartz tube that had an ultraviolet light on the outside of that tube. This method has been successfully used in a laboratory environment for research screening to verify the response of the various fractions to specific exposures to ultraviolet light.
Prior to the nineteen fifties, and prior to the development of the early mass quantity irradiator, it was impractical to treat blood through irradiation even though many of the benefits were well documented. During World War II, transfusions of blood plasma became commonplace. It was at this time that it became clear through the large scale of available documentation that transfusion of plasma from one person to another caused the spread of certain viral diseases among patients drawing from a common pooled blood plasma source. At this time, it became apparent that large scale irradiation to kill or immobilize these various microorganisms was essential to creating a safe blood plasma supply, with the irradiator as disclosed in the aforementioned patent being the first successful system for irradiating blood plasma on a commercial scale. This was a successful effort greatly increasing the availability of safe blood plasma supplies in the nineteen fifties.
Unfortunately, during the Korean war it appeared that the irradiation treatment was not successful for killing or immobilizing various strains of hepatitis and by 1960 commercial irradiation for human blood plasma pools basically ceased. In 1964, the World Health Organization published a statement that all pooled plasma from blood banks, plasma banks, and producers of plasma, could not be distributed for human transfusion. The commercial use of irradiators diminished to near zero. While certain applications remained viable, particularly for bovine blood plasma, the extremely reduced demand for commercial irradiators resulted in halting the continuing development of the technology.
More recently, irradiation has been found to be particularly successful in the inactivation of rabies virus for the manufacture of rabies vaccine. Of the less than twenty-five known commercial irradiators still in existence in the world the vast majority are used for producing rabies vaccine. On a lesser scale, the irradiators are also effective against and used for influenza virus, and at least one company in Italy and one in Japan, use the irradiator of the aforementioned reference to manufacture influenza vaccine.
Over the last several years, it has been determined that blood fractions irradiation may be a valuable treatment for immobilizing certain viruses and potentially placing the patients so infected in long term remission.
With the renewed interests in ultraviolet treatment of blood constituents, there is a pressing need for an improved, high volume irradiator apparatus. Moreover, the currently available technology, while very successful for its intended purpose over thirty-five years ago, relied very heavily on trial and error and the steady monitoring by experienced technicians. There remains a need for a commercial irradiator which is reliable independently of the high level of skill generally required with past machinery in order to assure that the promising new irradiation treatments can be duplicated on a commercial level.